What is the definition of gluLookAt?

The description of the gluLookAt is as follows:
Let
F=centerX-eyeXcenterY-eyeYcenterZ-eyeZ
Let UP be the vector upXupYupZ.
Then normalize as follows:
f=FF
UP″=UPUP
Finally, let s=f×UP″, and u=s×f.
M is then constructed as follows:
M=s⁡0s⁡1s⁡20u⁡0u⁡1u⁡20-f⁡0-f⁡1-f⁡200001 //??????
gluLookAt is equivalent to
glMultMatrixf(M);
glTranslated(-eyex, -eyey, -eyez);

Can you explain the description above?Especially the define of M,the line with ????.
Thank you very much.

The thing is, Alfonse is right in saying you don't need to use gluLookAt, because if you get the math behind it, you can write up a function yourself. I suspect the OP doesn't have a sufficient mathematical basis.